Guys...seriously...? What the hell?
It is just to buy time.
The plan is going to hit the ground, probably explode, and spread everything around in a big, giant, mess.
The CIA are led to believe everyone on the flight register: The CIA official, his men, Dr. Pavel, and one of the mercs are on board.
Bane transfuses blood from Pavel into the dead body and actually leaves the bag of blood behind.
If the body is somehow in-tact at all, it will have traces of Dr. Pavel's blood in it, if it isn't in tact at all, which is the most assured scenario, the bag of blood will be disintegrated and have Dr. Pavels blood spread everywhere all over the crime scene. The wreckage will be a complete cluster****. Blood over here, blood over there, evidence burning up, etc. ad infinitude...
Firstly, they will think it is a horrible accident, then they do some sweeping of the grounds for signs of foul play, when they finally get around to forensics they will first go for traces of blood because that is the easiest, they don't just skip to pulling out people's teeth and analyzing that if an easier source can be established because that stuff takes forever. That will throw them off the trail of Bane. Before they finally get around to finding something not quite right about the situation, they're ****ed. Bane has long gotten away with Dr. Pavel and is god knows where.
Now, let's put that crap to rest.